Since opera dumped presto (2013 if i am not wrong) opera for android has a hard time when it comes to password management.
On my android one device the stable opera is unable to save password on the login page of it's own forum....
Also there are numerous other websites where opera simply does not offer the "Save password?" option after hitting the login button.
God have mercy on your soul if you have to make a hard reset on your phone, after restoring opera, you have to login to your favourite sites one-by-one to make opera remember the passwords.
(of course only after you have imported all the speed dial "icons" ONE BY ONE, since only opera mini has the "import all" speeddial feature)
Probably this is the only mainstream browser app on play store that is unable to provide password management for five years. It is more than pathetic, that this is an issue in 2018.
So, i do not think that anyone should have high expectations about this topic, better clap your hands for more important developments like permanently shown search history and suggested search topics for this is opera only capable of since years and at the moment.

DI'd you change your sync settings in Android? When I received the update to 47 it was saying my sync password was invalid. So after verifying on desktop what my password was I fixed it, and it showed me the list of options for what to sync - and passwords was not enabled by default. After enabling the option everything was okay - though the next time I ran desktop it froze for several minutes. Fortunately only happened once.